Music problems with 3.0 on 2nd gen

For some reason sometimes if i nudge my ipod headphones and a song is playing (so that i accidentally pull it out a little or something, or maybe not im not wquite sure what happens or when it happens....?? maybe someone can confirm?) my music volume fades slowly down to ZERO, as if it were opening another app that needed the sound also. When i remove the headphones and play it on speaker mode, it does the exact same thing. The only way to fix it temporarily until the next time it happens is to respring my ipod. Anyone know a fix / have had this problem?